Service provider networks typically delivers services, such as digital television, high-speed Internet, Voice-over-IP (VoIP), etc., to customer premises. Also, the networks typically carry bi-directional traffic. For example, a typical cable network is a two-way hybrid fiber-coaxial (HFC) network that supports point-to-multipoint transmission in the downstream direction using digital signals or a mix of analog and digital signals, and multipoint-to-point transmission in the upstream direction. Downstream signals, which carry broadcast digital TV signals, Internet traffic, etc., are distributed via a fiber optic connection from a head-end to a node that converts the optical signals to electrical signals and then distributes the signals to customer premises via a tree and branch coaxial cable distribution network termed ‘cable plant’. Recently, service providers are running fiber to the customer premises to improve bandwidth. At the customer premises, terminal equipment supports the delivery of services, which may include video, data and voice services, to customers for example via cable modems. Upstream signals from the customer premises may carry phone and Internet traffic. The upstream signals propagate from the branches of the cable plant towards the headend of the network.
The upstream and downstream signals are prone to impairments originating at various locations in the network. There may be numerous devices, cable segments and connectors located between the fiber optic node and the customer premises equipment where defects can occur, and defects and impairments can occur at different customer premises that can impact the signal quality of other customer premises. Tracing a source of an impairment typically requires that a technician travels to different network locations and takes signal measurements to locate the sources of the impairments. Portable network testing devices currently used in the industry may help to identify certain types of defects by performing various signal measurements, such as spectral and noise measurements.